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Aug 18, 2019, 08:05 PM
Registered User
Thread OP
Help!

LiPos are dying on brand-new plane


I have a new Conscendo (ARF) which has now gone thru 3 LiPos without flying even once.
They were all new E-flite, High-Power Series, 1300mAh 3S 20C
I installed a new battery Saturday afternoon, yesterday, and it's been in the plane, in my car until now, 8pm Sunday. The weather wasn't very hot.
The store guy, Bill, charged it on a new Prophet Sport Li-Po to 90% which I'm pretty sure we checked with a new Electrifly CellMatch both of which I bought.
Current voltage is reading 1.4v on my old Microna multi-meter but 'nothing' on the CellMatch (all blank).
The previous battery lost its voltage(!) while I was charging it with an old E-flite adapter and an E-flite balancing charger so I assumed they were the cause.
Until yesterday I'd always used the multi-meter so one could, I assume, just say that that's the problem; but it seems to be working okay on a 2200mAh LiPo I've got and I haven't observed any weird behavior with it.
Can anyone think of another reaon for this? Maybe the ESC?
The plane is way past its warranty, so what diagnostics can I try? The store would be helpful I think, but it's a long drive.

Thanks,
Peter
Last edited by chatt; Aug 18, 2019 at 08:28 PM.
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Aug 18, 2019, 08:24 PM
I'm a balsa butcher
Make sure that there are no short circuits anywhere. I had a similar problem with a RX pack. Turned out to be the negative wire in the switch harness had been pushed hard onto the switch terminals on the back and had gone through the insulation.
Aug 18, 2019, 08:45 PM
Registered User
Thread OP
Thanks, I'll try that.
Aug 18, 2019, 09:21 PM
Registered User
Take ALL you meters & chargers & cables to the RC shop. Also the 3 batteries & the plane to test run the charged batteries.

I have 2... FMA Cell Pro 4 units that are ancient. It has a read out window with preset charging programs. I bought some plug adaptors for different plugs on batteries. I have a big old car battery with a small charger keeping it full.

put the FMA gator clips on the battery . Set the charger to the correct battery type & cell count. Pick a max charge current.

Plug in the battery. It charges then goes to balance cells. Then SHUTS COMPLETLY OFF. Great safety feature. It monitors all the STUFF a good charger should do during charging on the window.
Aug 18, 2019, 10:11 PM
Space Coast USA
hoppy's Avatar
Quote:
Originally Posted by chatt
I installed a new battery Saturday afternoon, yesterday, and it's been in the plane, in my car until now, 8pm Sunday. The weather wasn't very hot.

Peter

Was the battery plugged in from Saturday PM to Sunday PM?
Aug 18, 2019, 10:21 PM
Registered User
Wintr's Avatar
As hoppy has implied, the ESC will discharge a battery when it is connected, even if you don't run the motor. So, if 'installed' means connected to the ESC, you are what caused the battery to fail.
Aug 18, 2019, 10:40 PM
If it flies, I can crash it.
rocketsled666's Avatar
Since the OP asked if maybe the ESC was to blame, and the ESC can't be a factor if it's not plugged in, I am inclined to think that this means the ESC was connected for two days. That would unquestionably produce the reported result...
Aug 18, 2019, 10:53 PM
Registered User
Thread OP
It was installed as in ready for flight, for 24 hours; would that be enough for the battery to drain to 1.4 v?
Aug 19, 2019, 12:10 AM
Frankenstein recycled packs
rampman's Avatar
Quote:
Originally Posted by chatt
It was installed as in ready for flight, for 24 hours; would that be enough for the battery to drain to 1.4 v?
Ummmmm, YES.
ONLY plug in the battery when ready to fly.

Rick
Aug 19, 2019, 01:49 AM
Bombs away! Err...landing
Ira NZ's Avatar
Quote:
Originally Posted by chatt
It was installed as in ready for flight, for 24 hours; would that be enough for the battery to drain to 1.4 v?
So...You had a live plane sitting there, all the servos powered up, the ESC powered up, the RX powered up for 24 hours?

Um....Very likely, yeah, that could have drained the batteries. Hahahaha.
Aug 19, 2019, 01:57 AM
AeroDan
Don’t be embarrassed, chatt. My 59” Apprentice wound 90’ up a 100’ Eucalyptus Tree last spring. I waited too late to begin my base-leg. Vanished less then a week later.
Aug 19, 2019, 02:50 AM
Bombs away! Err...landing
Ira NZ's Avatar
Quote:
Originally Posted by Ira NZ
So...You had a live plane sitting there, all the servos powered up, the ESC powered up, the RX powered up for 24 hours?

Um....Very likely, yeah, that could have drained the batteries. Hahahaha.
Just out of curiosity and to get some hard numbers, I went and pulled down one of my planes to measure the current draw while just sitting powered up. it was drawing 110ma according to my wattmeter. Let's just round it off to 100. So would drain a 1300mah battery beyond the safe level in about 10 hours.

It was my Multiplex Twinstar, so two ESCs, but same number of servos as your Consendo I think. Maybe a little more current draw but close enough we're talking a few hours difference, not days.

Sooooo.....Yeah...There you go.

Also, Plush ESCs make the motors beep and wiggle every few seconds when you haven't actually properly armed them. Current jumps up to 300ma for a split second. I'd assume whatever ESC is in your plane does the same, so I don't know what you were doing.
Aug 19, 2019, 07:49 AM
Registered User

That battery would now be considered a severe fire risk by me.


CORRECTING A FEW WORDS THAT ARE CONFUSING>

I would fully discharge it. then garbage it.

I regularly RUN WAY DOWN TO less than 5 % LIFEPO4 cells...…………. for over 20 ? years in my portable cordlerss vacuum cleanerevery week. lost 5 % capacity with that kind of abuse...………….. It will not burst into flames like a LIPO.

The FMA charger senses the 5 % charge left & does a SUPER SLOW recharge . Works everytime.
Last edited by cyclops2; Aug 19, 2019 at 06:40 PM.
Aug 19, 2019, 11:40 AM
Registered User
Wintr's Avatar
One more point to make - for safety reasons, you should never connect the battery and ESC if the transmitter is off. I know modern ESCs should not start the motor without a signal from the receiver that indicates the transmitter is active, but there's always that one time that fail-safe fails.
Aug 19, 2019, 02:34 PM
Registered User

Remember


We are using HOBBY / TOYS !! There are NO safety requirements by any country about R C machines..... ALL: YOUR responsibility. It really is.


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